/*
============================================================================
Name        : Md5.cpp
Author      : 
Version     :
Copyright   : Your copyright notice
Description : CMd5 implementation
============================================================================
*/

#include "Md5.h"

// Constants for MD5Transform routine.
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

/*
static TText8 PADDING[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
*/

// F, G, H and I are basic MD5 functions.
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

// ROTATE_LEFT rotates x left n bits.
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/*
FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (TUint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}

#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (TUint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (TUint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (TUint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}

CMd5::CMd5()
{
}

CMd5::~CMd5()
{
}

CMd5* CMd5::NewLC()
{
	CMd5* self = new (ELeave)CMd5();
	CleanupStack::PushL(self);
	self->ConstructL();
	return self;
}

CMd5* CMd5::NewL()
{
	CMd5* self=CMd5::NewLC();
	CleanupStack::Pop(); // self;
	return self;
}

void CMd5::ConstructL()
{

}

const TDesC& CMd5::ComputeMD5(const TDesC& aText)
{
	MD5_CTX ctx;

	//init md5
	Initialize(&ctx);

	//Create input buffer
	HBufC8* input = HBufC8::NewL(aText.Length());
	input->Des().Copy(aText);

	//update with our string
	Update(&ctx, input->Ptr(), aText.Length());
	
	//create the hash
	TUint8* buff = new (ELeave) TUint8[16];

	Final(buff, &ctx);

	//converte the hash to a string and return it
	return ConvToString(buff);	

}

void CMd5::Initialize(MD5_CTX *context)
{
	context->count[0] = context->count[1] = 0;
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;

	context->buffer = new (ELeave) TUint8[64];
}

void CMd5::Update(MD5_CTX *context, const TUint8* input, TUint inputLen)
{
	TUint i, index, partLen;

	// Compute number of bytes mod 64
	index = (TUint)((context->count[0] >> 3) & 0x3F);

	// Update number of bits
	if ((context->count[0] += ((TUint32)inputLen << 3)) < ((TUint32)inputLen << 3))
	{
		context->count[1]++;
	}
	context->count[1] += ((TUint32)inputLen >> 29);

	partLen = 64 - index;

	// Transform as many times as possible.
	if (inputLen >= partLen) 
	{
		Md5_memcpy(&context->buffer[index], input, partLen);
		Transform(context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64) Transform(context->state, &input[i]);
		index = 0;
	}
	else
	{
		i = 0;
	}

	// Buffer remaining input
	Md5_memcpy(&context->buffer[index], &input[i], inputLen-i);
}

void CMd5::Md5_memcpy(TUint8* output, const TUint8* input, TUint len)
{
	for (TUint i = 0; i < len; i++) output[i] = input[i];
}

void CMd5::Transform(TUint32 state[4], const TUint8* block)
{
	TUint32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode(x, block, 64);

	// Round 1
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */

	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	//Zeroize sensitive information.
	Md5_memset(x, 0, sizeof(x));
}

void CMd5::Decode(TUint32* output, const TUint8* input, TUint len)
{
	TUint i, j;
	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((TUint32)input[j]) | (((TUint32)input[j+1]) << 8) |
			(((TUint32)input[j+2]) << 16) | (((TUint32)input[j+3]) << 24);
}

void CMd5::Md5_memset(TUint32* output, TInt value, TUint len)
{
	for (TUint i = 0; i < len; i++) ((char *)output)[i] = (char)value;
}

void CMd5::Final(TUint8* digest, MD5_CTX *context)
{
	TUint8* bits = new (ELeave) TUint8[8];

	TUint index, padLen;

	// Save number of bits
	Encode(bits, context->count, 8);

	// Pad out to 56 mod 64.
	index = (TUint)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	
	TUint8 PADDING[64] = {
		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	};
	
	Update(context, PADDING, padLen);

	// Append length (before padding)
	Update(context, bits, 8);

	// Store state in digest
	Encode(digest, context->state, 16);

	// Zeroize sensitive information.
	Md5_memset((TUint32*)context, 0, sizeof(*context));
}

void CMd5::Encode(TUint8* output, TUint32 *input, TUint len)
{
	TUint i, j;
	for (i = 0, j = 0; j < len; i++, j += 4) 
	{
		output[j] = (TUint8)(input[i] & 0xff);
		output[j+1] = (TUint8)((input[i] >> 8) & 0xff);
		output[j+2] = (TUint8)((input[i] >> 16) & 0xff);
		output[j+3] = (TUint8)((input[i] >> 24) & 0xff);
	}
}

const TDesC& CMd5::ConvToString(TUint8* bytes)
{
	TBuf<32> asciihash;
	for (TInt i = 0; i < 16; ++i)
	{
		asciihash.AppendFormat(_L("%02x"), bytes[i]);
	}	
	return asciihash;
}
